Lessons from ambient intelligence prototypes for universal access and the user experience.

A cognitive evaluation was conducted on a sample of prototypes and identified implications for universal access in ambient intelligence environments, using a model of cognitive factors. A study of user experience, with two intelligent prototypes, one less intelligent and irritating showed a substantial impact of negative emotions on user performance that was independent of age. Significantly, performance changed but ratings of perceived difficulty did not, showing that they do not always correlate well. A case study of the user-participative development of a PDA for use with ambient intelligence confirmed the importance of emotional factors in inclusive design.